Fluid-operated percussive tool



H. I. STAGE.

' FLUID OPERATED PERCUSSIVE TOOL.

APPLICATION FILED nan. 24. 1920.

' 1,353,796; .PatentedSept. 21,1920.

HAROLD I. STAGE, OF EASTON, PENNSYLVANIA, ASSIGNOR T0 INGERSOLL RAND CO M- PANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

FLUID-OPERATED EERCUS SIVE TOOL.

Specification of Letters Patent. Patented Sept. 1920.

Application filed February 24, 1920. Serial No. 360,564.

der, and controlling means are provided for the exhaust from the cylinder, in order to prolong the period of expansion and increase the efficiency while decreasing the power consumption of the tool.

The primary object of the present invention is to produce a tool of this class in which the closing of the exhaust is retarded in a simple and effective manner, thus increasing the efiiciency of the tool. My device enables the exhaust to be kept open from each end of the cylinder as long as practicable, without opening the exhaust passages any sooner than with the exhaust valves heretofore used.

' The invention consists of combinations of elements and arrangement of parts sub stantially as hereinafter described and claimed, for carrying out the above objects and a preferred embodiment of the invention is illustrated in the accompanying drawings, only so much of a percussive tool being shown as will be necessary to an understanding of the invention and its gen- In the drawings, Figure 1 is a diagrammatic view partly in longituchnal section through the cylinder of a tooland partly broken away, showing the fluid operated piston at the end of its forward stroke, and

Fig. 2 is a similar view showing the piston at the end of its rearward stroke.

- In bothFigsJ 1 and 2, itis to be understood that the cylinder and valve construction are merely diagrammatic with the working parts all shown in the same vertical plane for clearness, and the cylinder is shown in one piece for simplicity, while in actual practice the cylinder would be formed with the usual separable elements, including a front head, a back head, and any 'ated. p teferring to the drawings, 1 have chosen v the various working and dependent other necessary elements disposed as vdesired, to enable the working parts to be efliciently constructed, assembled and operto illustrate my invention in connection with a fluid operated percussive tool having a cylinder A constructed with a vdifferential bore and having a differential piston ham.-

mer B operating therein, adapted to strike the drill steel (J. Fluid pressure admitted through the inlet D is preferably constantly maintained on one of the forwardly driving formed at the reduced portionof the piston. The other driving pressure areas of the pressure areas of the'piston, in this instance upon'the pressure area formed by thevrearward shoulder E of the enlarged piston head piston at the ends of the cylinder formed by i 5% the forward end G of the enlarged head F and the rearward end H of the smaller head J are intermittently supplied with fluid pressure through suitable ports K and L and passages O and P controlledb'y the headsFandJ. w i

The heads and J are preferablyconnected as shown by a reduced neck Q, which permits admission of motive fluid alternately to the ends of the cylinder. The forward bore j .R of the cylinder oflarger diameter is provided with the main exhaust port S, and the rearward smaller bore T is provided with the main exhaust-port U, forexhausting the cylinder formed by the bores R and T of different ends of the cylinder. Intermediate the for- 1,

ward and rearward chambers municates, and from which intermediate chamber the fluid pressure s distributed to controlling parts of the tool. I

The present invention is particularly concerned with the exhausting of the intermittently supplied ends of the cylinder, and f in accordance with my present invention, auxiliary valve controlled means are provided for maintain ng the exhaust open after either one of the main exhaustports S and U is'closed in theoperation of the tool. I preferably provide separate and indifferentially acting exhaust valves WV and X, one for-each end of the cylinder, conveniently controllingthe ex haust through an auxiliary exhaust port Y.

These differential exhaust valves W and X may be constructed in any suitable manner, but as shown each is formed with an en larged head a and a smaller head 6 connected by reduced neck 0. The valves are preferably seated in suitable valve seats formed in the valve casing (Z which may be set into the cylinder walls in the desired positions, preferably over the admission ports K and L as shown.

In this instance and as a convenient and suitable construction, the ai xiliary exhaust port Y is located in a posi n in the cylinder wall intermediate or between the admis sion passages O and P so tnat these same passages be utilized as auxiliary exhaust passages, and the means for admitting the fluid to the ends of the cylinder may also be said to include means for controlling the exhaust from the cylinder, because portions of the same elements have both functions, according to the movements of the piston B.

As shown, the auxiliary exhaust port Y communicates with an exhaust passage 6 leading to the forward exhaust valve casing (5 at the port 9 and also with an exhaust passage leading to the rearward exhaust valve casing d at the port it, the two passages e and 7' together conveniently forming one passage. The port in the forward valve casing ul communicates with the forwarch passage 0 and a port 7c in the rearward valve casing (Z communicates with the rearward passage P. One of the differential pressure surfaces of each valve 3V and X is constantly subjected to the fluid pressure in the tool, in this instance the smaller heads 5 of the valves being subjected to this pressure through the passages 0 and p leading from the annular chamber V to the spaces in the valve casings behind said head Z).

In the operation of the tool, let it be assumed that the piston B is at the forward end of its stroke as shown in Fig. 1 and is ward passage P, around valve X and out through auxiliary exhaust port Y, until the port L is uncovered by the piston head J, which causes the valve X to be thrown to the position indicated in Fig. 2, closing the auxiliary exhaust passage 7 and opening the rearward passage P to the admission of working fluid pressure from the central constant pressure chamber V to the rear end of the cylinder for the commencement of the forward stroke.

011 the forward stroke, the valve N which has been thrown to the position indicated in Fig. 2, owing to the closing of the port K by the enlarged head F of the piston on the rearward stroke, permits the exhaust from the front end of the [cylinder to pass through the forward passage 0 and the auxiliary exhaust port Y after the main exhaust port 5 is closed, until the port if is again uncovered by the head F on the forward stroke, as shown in Fig. 1, at which time the cycle commences again.

I claim and desire to obtain by Letters Patent the following:

1. in a fluid operated percussive tool, a cylinder having a differential bore and a differential piston operating therein, mes-is: for constantly maintaining fluid pressure on one of the forwardly driving 1 )ressure an .s of said piston and means for intermittentm supplying fluid pressure to the other driving pressure areas of said piston, including exhaust passages for exhausting the fluid pressure from said intermittently supp ied areas and independent differential for controlling said passages in accordance with the movements of the piston.

2. ln a fluid operated percussive tool, a cylinder having a differential bore and differential. piston operating therein, means for constantly maintaining fluid pressure on one of the forwardly driving pressure areas of said piston and means for intermittently supplying fluid pressure to the other driving pressure areas of said piston, including exhaust passages for exhausting the fluid pressure from said intermittently supplied areas and independent differential valves for controlling said passages in accordance with the movements of the piston, each of said valves being constantly subjected to fluid pressure on one differential pressure area.

3. In a fluid operated percussive tool, a cylinder, a piston therein having an enlarged head, a smaller head at the rear of said enlarged head, and a reduced neck connecting said heads, said neck permitting admission of motive fluid alternately to the ends of the cylinder, the heads controlling such admission, means for constantly main taining fluid pressure on the forwardly acting pressure area of the said enlarged head, and means for exhausting said cylinder ends including independent difi'erentially acting exhaust valves.

4. In a fiuid operated percussive tool, a cylinder, a piston therein having an enlarged head, a smaller head at the rear of said enlarged head, and a reduced neck connecting said heads, said neck permitting ad mission of motive fluid alternately to the ends of the cylinder, the heads controlling such admission, means for constantly main taining fluid pressure on the forwardly acting pressure area of the said enlarged head, and means for exhausting said cylinder ends including independent differentially acting exhaust valves constantly subjected to fluid pressure on one of their pressure areas.

5. In a fluid operated percussive tool, a cylinder having an annular chamber intermediate its ends and means to supply fluid under pressure to such chamber, fluid passages leading to the opposite ends of the cylinder, a piston having a rearwardly facing shoulder intermediate its ends subjected at all times to the pressure and having other portions to serve as valves to intermittently permit the fluid pressure to pass from the intermediate chamber through said passages alternately to the opposite ends of the piston, including exhaust passages communicating with said fluid passages and independent diflerentially acting valves controlling said exhaust passages in accordance with the movements of the piston.

6. In a fluid operated percussive tool, a cylinder having an annular chamber intermediate its ends and means to supply fluid under pressure to such chamber, fluid passages leading to the opposite ends of the cylinder, a piston having a rearwardly facing shoulder intermediate its ends subjected at all times to the pressure and having. other portions to serve as valves to intermittently permit the fluid pressure to pass from the intermediate chamber through said passages alternately to the opposite ends of the piston, including exhaust passages communicating with said fluid passages and independent differentially acting valves controlling said exhaust passages in accordance with the movements of the piston, each of said valves being constantly subjected on one pressure surface to the fluid under pressure. I

7. In a fluid operated percussive tool, a

cylinder, a piston in said cylinder having two pressure areas for driving it forward and a pressure area for driving it rearward,

fluid passages arranged to admit fluid pressure constantly to one of said forwardly operating pressure areas, and alternately to the other forwardly operating pressure area and to said rearwardly operating pressure area, passages from said cylinder for alternately exhausting the fluid pressure from said alternately supplied pressure areas, an auxiliary exhaust passage adapted to aflord additional exhaust from the alternately supplied pressure areas, and independent valves for controlling the said auxiliary exhaust passage in accordance with the movements of the piston.

In testimony whereof I have hereunto set my hand.

HAROLD I. STAGE. 

